A relay device includes a first communication unit that receives a request including processing object data from a client device; a data processing unit that obtains a first processing result by performing a relay-device-side process of equivalent algorithm to that of a server-side process, which is performed by a server, on the processing object data; a second communication unit that transmits the request to the server, and receives a second processing result, which corresponds to the first processing result and is obtained by performance of the server-side process on the processing object data, from the server as a response; and a control unit that determines whether the second processing result has been transmitted to the client device. When the second processing result has not been transmitted to the client device, the first communication unit transmits the first processing result to the client device.